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Maintaining Fluid and Electrolyte Balance

Concepts of Fluid Balance

Functions of body fluids

Fluid compartments

Electrolytes

Movement of fluids and electrolytes

Regulation of fluid balance

Problems of fluid balance

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Functions of Body Fluids

Body needs: 1500 mL daily 700 mL from food we eat 300 mL from oxidation of food

Functions Makes half the body weight Transports nutrients and wastes to and from cells Acts as solvent for electrolytes and nonelectrolytes Facilitates digestion and elimination Maintains acid-base balance Lubricates joints and other body tissues

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Fluid Compartments

Intracellular fluid compartment Contain 70% of body fluids Fluid loss at cellular level affects entire body

Extracellular fluid compartment Contain 30% of body fluids Intravascular fluids Interstitial fluids Transcellular fluids

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Electrolytes

ElectrolyteElectrolyte Normal Plasma ValueNormal Plasma Value

SodiumSodium 135 to 145 mEq/L135 to 145 mEq/L

PotassiumPotassium 3.5 to 5.0 mEq/L3.5 to 5.0 mEq/L

CalciumCalcium 4.5 to 5.5 mg/dL4.5 to 5.5 mg/dL

MagnesiumMagnesium 1.5 to 2.5 mg/dL1.5 to 2.5 mg/dL

ChlorideChloride 98 to 106 mEq/L98 to 106 mEq/L

PhosphorusPhosphorus 1.2 to 3.0 mg/dL1.2 to 3.0 mg/dL

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Movement of Fluids and Electrolytes

Osmosis Hypotonic Hypertonic

Diffusion Active transport Filtration

Colloid osmotic pressure Hydrostatic pressure

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Regulation of Fluid Balance

Thirst Intake of fluids

Lymphatic system “Sponging up”

Neuroendocrine system Hormones

Gastrointestinal system Absorbs—secretes—reabsorbs

Renal system Works with neuroendocrine system to regulate volume

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Problems of Fluid Balance Deficient fluid volume

Hypovolemia Dehydration

Excess fluid volume Hypervolemia Water intoxication

Electrolyte imbalance Deficit or excess of one or more electrolytes

Acid-base imbalance Respiratory acidosis and respiratory alkalosis Metabolic acidosis and metabolic alkalosis

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Factors Affecting Fluid Balance

Lifestyle factors Nutrition Exercise Stress

Physiological factors Cardiovascular Respiratory Gastrointestinal Renal Integumentary Trauma

Developmental factors Infants and children Adolescents and middle-

aged adults Older adults

Clinical factors Surgery Chemotherapy Medications Gastrointestinal intubation Intravenous therapy

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Assessment of Fluid Balance

General Focused assessment for deficient

fluid volume Focused assessment for excess fluid

volume Focused assessment for associated

problems

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General Assessment

Health history Chief complaint Past history of

illnesses

Physical examination Standard clinical

measurements Weighing the client Input and output Assessing edema

Diagnostic tests Plasma sodium Plasma osmolality Urine osmolality Hematocrit Blood urea nitrogen

(BUN)

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Focused Assessment for Deficient fluid volume

Defining characteristics Extracellular Intracellular

Related factors The acuteness of the loss The severity of the loss The client’s age and state of health The degree to which the client combats the deficit

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Focused Assessment for Excess fluid volume

Defining characteristics Extracellular Intracellular

Related factors Any increase in fluid intake Any increase in sodium intake Increase in capillary permeability Protein loss The client’s response to fluid excess

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Focused Assessment for Associated Problems Electrolyte imbalances

Fluid imbalances rarely exists without electrolyte imbalance

Anticipate the risk for imbalance Metabolic acidosis

End-stage renal disease Severe diarrhea Hypoxia Hyperglycemia

Metabolic alkalosis Consumption of excessive bicarbonate products Loss of excessive potassium and hydrochloric acid

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Diagnosis

Deficient fluid volume or Risk for deficient fluid volume

Excess fluid volume or Risk for excess fluid volume

Related nursing diagnoses Fatigue Anxiety Ineffective health maintenance Imbalanced nutrition Impaired skin integrity Impaired tissue perfusion Impaired gas exchange Constipation Impaired oral mucous membranes Disturbed sleep pattern

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Planning (Expected Outcomes)

Deficient fluid volume Increase in fluid intake Moist mucous membranes Absence of tongue furrows

Excess fluid volume Decrease in peripheral edema Weight loss Decrease in fatigue and weakness

Associated problems

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Interventions

To reduce the risk of deficient fluid volume Teaching client about fluid needs Preventing excessive fluid deficits Restoring lost fluids

To increase fluid volume Restoring fluid balance Preventing further loss Instituting rehabilitative care Administering intravenous therapy

To decrease fluid volume Restoring fluid balance Preventing complications Instituting rehabilitative care

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Interventions

To balance electrolyte levels General interventions

o Nutrition is the key Sodium imbalance: hyponatremia or hypernatremia Potassium imbalance: hypokalemia or hyperkalemia Calcium imbalance: hypocalcemia or hypercalcemia Magnesium imbalance Phosphate imbalance

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Intravenous Therapy

Types of intravenous (IV) solutions

Categorized by osmolality: how solution affects other fluids Isotonic Hypotonic Hypertonic

Sites for IV therapy

Potential complications Infiltration Phlebitis Infection Air embolism Allergic reaction Circulatory overload

Care of IV site Peripheral Central

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Evaluation

The time frame for evaluating fluid or electrolyte

imbalance varies with the urgency of the imbalance.

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